Stone-like structural material



Patented Feb. 26, 1935 1,992,488

UNIT-ED TATE-s AT NT ew tone, Incorporated, La Fayette, 11111., a corpora-v tion of Indiana N Drawing. Application September 19, 1932,

Serial No. 633,924

6 Claims. (Cl. 18-475) This invention relates to a novel stone-like One specific practical example of my process structural material and includes the product oband product is as follows: 100 parts pulverized tained and the process of making same. limestone, 20 parts lime hydrate, and 15 parts I have discovered that a reaction of a mixture water are intimately mixed to form a workable of alkaline earth carbonates and alkaline earth mass; the mass is then formed into shapes, and 5 bases when subjected to moist heat eifects a the shapes subjected to moist heat in a suitable change in the chemical or physical state of the oven or retort at a temperature of about 320 dematerials which results in a product possessing grees Fahrenheit for a period of about 2 hours excellent strength and other useful physical propuntil the desired reaction occurs. The resulting 10 erties rendering it suitable for structural purproduct has a compressive strength of approx- 10 poses. I imately 4000 pounds per sq. in. and has physical In accordance with my invention or discovery properties comparable to those of natural lime- I intimately mix finely divided limestone or stone or dolomite. The proportions temperature, dolomite with an alkaline earth base, such as and time given above are illustrative and not lime hydrate, and sufficient water to form a fairly definitive; l5 compact thoroughly wetted mass; which mass is It has heretofore been attempted to produce then molded into shapes and indurated by subsynthetic stone or building material by subjectjecting same to moist heat in an oven or coning a mixture of limestone and lime hydrate to tainer until the desired reaction occurs. action of carbonic acid gas. The difference be- Very fine limestone and dolomite wastes octween the induration with- CO2 gas and simple 20 our in quarries and mills where the natural stone moist heat is very great chemically. Indurating is sawed and finished. These fine wastes can be with CO2 gas produces a knitting together of utilized in my process, or larger sized waste pieces the limestone particl s y the carbonation of may be pulverized to suitable fineness. the lime, resulting in a CaCOa mixture. In my Since my product is a result of chemical union process I presumably obtain by chemical reaction 25 or physical change, the raw material must be a basic carbonate CaCOa, Ca(OH)2 and produce finely divided and most of it should pass a 200 an essentially difierent product fromrthat promesh screen: The control of fines is important to duced by C02 gas. the final properties of my product and the com- My process differs from previous processes in pleteness of the chemical or physical union. The that the reaction occurs between the ingredients fine limestone or dolomite and an alkaline earth during induration in the presence of moist heat; base (such as lime hydrate) are incorporated no carbon dioxide gas or the like is used. My thoroughly and completely withsufiicient water to product is obtained by compacting the thoroughly insure proper particle contact, which may be mixed ingredients to bring about particle contact accomplishedinstandard commercial mixing maand the subsequent induration under controlled 35 chines. After the ingredients have been thormoisture and heating conditions. oughly mixed, the moist material is formed into This product may be used to bind together shapes in molds, or by other suitable means; and during the indurating step coarser particles of such damp molded shapes are then subjected to Waste material such as limestone, dolomite, or moist heat in a suitable oven or container until other aggregates, which causes a resemblance to the desired reaction occurs. the natural product itself with similar physical In producing my product I employ: p De and p nc (1) Alkaline earth carbonates, such as lime- Ic1aim:- stone, a chemical compound formed by union of 1. The herein described process of producing H2COs=CaCO3+2H2O, and ing a finely divided alkaline earth carbonate and (2) Alkaline earth bases, such as lime hydrate an alkaline earth base, moistening same, shapf (CaOHz). ing the mass and subjecting the shapes to moist Normally no reaction would be expected beheat until they are converted into the desired tween these two materials, cited above. Howmaterial. ever, I have discovered that something unusual 2. The herein described process of producing does take place under exposure to moist heat a stone-like structural material; consisting in inwhich I tentatively explain on chemical grounds, timately mixing finely divided lime-stone, lime as: CaCO3+Ca(OH)2+nH2O=CaCO3, Ca(OH)2+ hydrate and sufiicient water to thoroughly wet a base (CaOI-Iz) and an acid (H2003) Ca(OH)2+ Structural material, consisting in intimately mix- :vI-IzO. the mass, shaping the mass and indurating the 55 shapes by moist heat until they are converted by reaction into the desired material.

3. The herein described process of producing a stone-like structural material consisting in intimately mixing finely divided dolomite, lime hydrate and sufficient water to thoroughly wet the mass, shaping the mass and indurating the shapes by subjecting them to moist heat until they are converted into the desired material.

4. The herein described structural material produced by intimately mixing a finely divided alkaline earth carbonate and an alkaline earth base, moistening same, shaping the mass and subjecting the shapes to moist heat until they are converted by reaction into the desired material.

5. The herein described stone-like structural material, produced by intimately mixing finely divided limestone, lime hydrate and sufiicient water to thoroughly wet the mass, shaping the mass and indurating the shapes by moist heat until they are converted into the desired material.

6. The herein described stone-like structural material produced by intimately mixing finely divided dolomite, lime hydrate and sufiicient water to thoroughly wet the mass, shaping the mass and indurating the shapes by subjecting them to moist heat until theyare converted by reaction into the desired material.

PAUL W. JONES. 

